﻿HISTORY 
  OF 
  THE 
  DISEASES 
  IN 
  THE 
  UNITED 
  STATES. 
  211 
  

  

  show 
  this 
  Micrococcus 
  spontaneously 
  if 
  kept 
  for 
  a 
  little 
  time 
  in 
  confinement, 
  and 
  

   the 
  investigation 
  consequently 
  remains 
  in 
  an 
  unfinished 
  state. 
  The 
  fact 
  is 
  worthy 
  

   of 
  special 
  remark 
  that 
  lots 
  of 
  chinch-bugs 
  kept 
  for 
  several 
  days 
  in 
  the 
  dry 
  air 
  of 
  

   the 
  laboratory, 
  imprisoned 
  under 
  a 
  large 
  bell 
  jar 
  on 
  a 
  varnished 
  table, 
  continued 
  to 
  

   die 
  in 
  numbers 
  with 
  this 
  bacterial 
  disease, 
  and 
  finally 
  all 
  perished. 
  Other 
  fungus 
  

   attacks 
  were 
  invariably 
  arrested 
  by 
  such 
  conditions, 
  the 
  air 
  being 
  probably 
  too 
  dry 
  

   to 
  permit 
  the 
  Entomophthora 
  or 
  the 
  Sporotrichum 
  to 
  flourish. 
  

  

  With 
  regard 
  to 
  the 
  Sporotrichum, 
  Professor 
  Forbes 
  begins 
  by 
  saying: 
  

   The 
  unquestionably 
  parasitic 
  character 
  of 
  this 
  fungus, 
  the 
  terrific 
  destruction 
  of 
  

   chinch-bugs 
  to 
  which 
  it 
  certainly 
  contributed 
  in 
  1888 
  and 
  1889 
  in 
  Illinois, 
  the 
  ease 
  

   with 
  which 
  it 
  may 
  be 
  cultivated 
  artificially 
  in 
  quantities, 
  and 
  the 
  great 
  variety 
  of 
  

   insects 
  which 
  we 
  have 
  found 
  it 
  to 
  attack, 
  make 
  it 
  one 
  of 
  the 
  more 
  important 
  fungus 
  

   parasites 
  of 
  insects 
  from 
  an 
  economic 
  point 
  of 
  view, 
  and 
  will 
  doubtless 
  justify 
  the 
  

   fullest 
  treatment 
  possible 
  at 
  the 
  present 
  time. 
  

  

  Professor 
  Forbes 
  then 
  reviews 
  his 
  observations 
  on 
  the 
  presence 
  of 
  this 
  dis- 
  

   ease 
  among 
  chinch-bugs 
  in 
  Illinois. 
  (See 
  pp. 
  207, 
  208 
  of 
  this 
  report.) 
  After 
  

   describing 
  the 
  fungus, 
  he 
  discusses 
  in 
  detail 
  his 
  "culture 
  and 
  infection 
  ex- 
  

   periments," 
  which 
  discussion 
  I 
  quote 
  in 
  full, 
  as 
  follows 
  : 
  

  

  Several 
  attempts 
  made 
  in 
  the 
  fall 
  of 
  1888 
  to 
  cultivate 
  the 
  Sporotrichum 
  in 
  beef 
  

   broth 
  by 
  dropping 
  infected 
  chinch-bugs 
  into 
  the 
  tube 
  resulted 
  only 
  in 
  the 
  growth 
  of 
  

   a 
  mixed 
  mycelium, 
  (partly 
  Mucor,) 
  in 
  which 
  nothing 
  resembling 
  the 
  fruiting 
  bodies 
  

   of 
  Sporotrichum 
  appeared. 
  These 
  experiments, 
  therefore, 
  must 
  be 
  considered 
  as 
  

   failures. 
  

  

  My 
  attention 
  was 
  next 
  called 
  to 
  the 
  artificial 
  culture 
  of 
  this 
  fungus 
  by 
  the 
  receipt, 
  

   May 
  15, 
  1891, 
  from 
  Mr. 
  Roland 
  Thaxter, 
  of 
  a 
  tube 
  of 
  agar 
  containing 
  an 
  abundant 
  

   growth 
  of 
  it, 
  derived 
  originally 
  from 
  larvae 
  of 
  Copipanolis 
  vernalis, 
  which 
  he 
  was 
  rear- 
  

   ing 
  in 
  a 
  breeding 
  cage. 
  From 
  this 
  culture, 
  which 
  was 
  fruiting 
  abundantly 
  when 
  re- 
  

   ceived, 
  agar 
  cultures 
  were 
  repeatedly 
  grown 
  here; 
  and 
  from 
  these 
  were 
  also 
  begun 
  

   various 
  successful 
  cultures 
  in 
  other 
  media. 
  These 
  were 
  all 
  made 
  in 
  test 
  tubes 
  by 
  

   the 
  usual 
  processes 
  of 
  sterile 
  bacterial 
  cultures, 
  the 
  nutrient 
  material 
  being 
  beef 
  

   broth, 
  prepared 
  as 
  for 
  the 
  culture 
  of 
  bacteria 
  and 
  used 
  to 
  saturate 
  corn 
  meal, 
  mid- 
  

   dlings, 
  bran, 
  and 
  sawdust. 
  In 
  all 
  these 
  experiments, 
  each 
  two 
  or 
  three 
  times 
  repeated, 
  

   the 
  Sporotrichum 
  spores 
  germinated 
  freely 
  and 
  promptly, 
  the 
  visible 
  growth 
  begin- 
  

   ning 
  in 
  about 
  36 
  hours 
  and 
  increasing 
  rapidly 
  at 
  the 
  ordinary 
  temperature. 
  It 
  was, 
  

   however, 
  much 
  more 
  profuse 
  in 
  the 
  corn 
  meal 
  mixture 
  than 
  in 
  any 
  of 
  the 
  others, 
  next 
  

   in 
  the 
  middlings, 
  and 
  slowest 
  in 
  the 
  saturated 
  sawdust. 
  The 
  heads 
  of 
  spores 
  began 
  

   to 
  appear 
  within 
  two 
  or 
  three 
  days, 
  and 
  the 
  stage 
  of 
  ripening 
  — 
  indicated 
  by 
  the 
  ready 
  

   detachment 
  of 
  the 
  spores 
  on 
  jarring 
  or 
  shaking 
  — 
  was 
  reached 
  in 
  from 
  9 
  to 
  12 
  days 
  

   from 
  the 
  beginning 
  of 
  the 
  experiment. 
  The 
  growth 
  was 
  upon 
  the 
  surface 
  of 
  all 
  these 
  

   masses, 
  and 
  nowhere 
  penetrated 
  the 
  interior, 
  except 
  where 
  the 
  medium 
  was 
  loosely 
  

   compacted, 
  so 
  that 
  air 
  spaces 
  occurred 
  within 
  it. 
  As 
  examples 
  of 
  the 
  process 
  of 
  de- 
  

   velopment, 
  the 
  notes 
  of 
  the 
  two 
  following 
  cultures 
  may 
  be 
  given: 
  

  

  June 
  9, 
  prepared 
  beef 
  broth 
  by 
  the 
  usual 
  method 
  for 
  pure 
  bacterial 
  culture, 
  ster- 
  

   ilized 
  it, 
  and 
  heated 
  corn 
  meal 
  almost 
  to 
  a 
  scorching. 
  Mixed 
  the 
  two 
  to 
  a 
  thick 
  

   batter, 
  and 
  put 
  into 
  a 
  test 
  tube, 
  inclined 
  to 
  give 
  a 
  sloping 
  surface. 
  Plugged 
  with 
  

   cotton 
  and 
  sterilized 
  at 
  temperature 
  of 
  100° 
  centigrade 
  for 
  half 
  an 
  hour. 
  Sporotri- 
  

   chum 
  spores 
  from 
  an 
  agar 
  culture 
  sown 
  on 
  this 
  mixture 
  June 
  11, 
  8 
  o'clock 
  a. 
  m. 
  June 
  

   13, 
  8 
  o'clock 
  a. 
  m., 
  growth 
  of 
  the 
  fungus 
  has 
  begun. 
  June 
  14, 
  growing 
  freely. 
  June 
  

   15, 
  spreading 
  very 
  rapidly. 
  June 
  16, 
  growth 
  spreading 
  freely 
  and 
  entering 
  little 
  

   crevices 
  at 
  the 
  margins 
  of 
  the 
  mass. 
  Heads 
  of 
  spores 
  beginning 
  to 
  form. 
  June 
  17, 
  

  

  